745 
1888 - 89 .] Dr T. R. Fraser on Strophanthus hispidus. 
electric stimulation of its motor nerve fails to cause any effect. 
After the twitching contractions have ceased, the motor nerve 
regains its influence; and the contractions of the entire muscle, 
which are now produced by stimulating the nerve, illustrate the 
condition of increased tonicity produced by Strophanthus. The 
muscle curve is altogether different from the normal curve. The 
muscle contracts actively, but, after having contracted, it relaxes 
with great tardiness ; and it is only after several revolutions of a 
rapidly revolving cylinder that the curve gradually falls to the 
abscissa. [Curves were shown.] 
When Strophanthus is administered by subcutaneous injection 
to a frog, one of whose muscles, without otherwise deranging its 
normal relations, is attached to a lever writing on a revolving 
cylinder, similar changes in contractility are observed, but they are 
less in degree. [Curves were shown.] 
Owing partly to the circumstance that a larger quantity of any 
substance introduced into the blood is in any given time conveyed 
to the heart than to any other individual organ or structure 
of the body, the action of Strophanthus is exerted with the 
greatest energy and activity upon the heart. With very minute 
doses, its contractions are rendered slower and more perfect and com- 
plete ; and with larger doses, the diastolic dilatation of its chambers 
is reduced until dilatation disappears altogether, and the heart ceases 
to beat because its muscle can no longer relax. The condition of 
the muscle becomes the same as that of the other striped muscles 
under the influence of large doses. It is hard, non-contractile under 
stimulation, and acid in reaction, — the condition of true rigor mortis 
having been produced as the ultimate stage in the sequence of events 
in the pharmacological action of Strophanthus. These changes 
occur even although all the nerve connections of the heart are 
severed, or the vagus nerve is paralysed by the previous adminis- 
tration of atropine. 
The power of an extremely minute quantity of Strophanthus to 
produce these effects on the heart was illustrated in a series of 
experiments, in which an attempt was made to determine the 
minimum quantity required to paralyse the frog’s heart. The 
heart was attached to an apparatus allowing it to pump from a 
reservoir a fluid which sustained its nutrition for many hours, 
